Glowing in the Dark

Everybody's doing itCounterillumination is something you need to see to believe. One testament to its effectiveness is the enormous numbers of animals that use it. They include the benttooth bristlemouth (which, notably, is the most common vertebrate on the planet), lantern fish, viperfish, scaly dragonfish, krill, and squid. The squid in this image, Abralia veranyi, is such a master of disguise that it can change the color of its belly lights depending on whether it is counterilluminating against sunlight or moonlight.